@segment/analytics-react-native

The hassle-free way to add Segment analytics to your React-Native app.

⚠️ This readme covers analytics-react-native 2.0.0 and greater. The code and readme for analytics-react-native versions below 2.0.0 can be found on the analytics-react-native-v1 branch. On May 15, 2023, Segment will end support for Analytics React Native Classic, which includes versions 1.5.1 and older. Upgrade to Analytics React Native 2.0.

Table of Contents

• @segment/analytics-react-native
  • Table of Contents
  • Installation
    • Expo
    • Permissions
  • Migrating
  • Usage
    • Setting up the client
    • Client Options
    • iOS Deep Link Tracking Setup
    • Native AnonymousId
    • Usage with hooks
    • useAnalytics()
    • Usage without hooks
  • Client methods
    • Track
    • Screen
    • Identify
    • Group
    • Alias
    • Reset
    • Flush
    • (Advanced) Cleanup
  • Automatic screen tracking
    • React Navigation
    • React Native Navigation
  • Plugins + Timeline architecture
    • Plugin Types
    • Destination Plugins
    • Adding Plugins
    • Writing your own Plugins
    • Supported Plugins
  • Controlling Upload With Flush Policies
  • Adding or removing policies
    • Creating your own flush policies
  • Handling errors
    • Reporting errors from plugins
  • Contributing
  • Code of Conduct
  • License

Installation

Install @segment/analytics-react-native, @segment/sovran-react-native and react-native-get-random-values:

yarn add @segment/analytics-react-native @segment/sovran-react-native react-native-get-random-values
# or
npm install --save @segment/analytics-react-native @segment/sovran-react-native react-native-get-random-values

If you want to use the default persistor for the Segment Analytics client, you also have to install react-native-async-storage/async-storage.

yarn add @react-native-async-storage/async-storage 
# or
npm install --save @react-native-async-storage/async-storage

Note: If you wish to use your own persistence layer you can use the storePersistor option when initializing the client. Make sure you always have a persistor (either by having AsyncStorage package installed or by explicitly passing a value), else you might get unexpected sideeffects like multiple 'Application Installed' events. Read more Client Options

For iOS, install native modules with:

npx pod-install

⚠️ For Android, you will have to add some extra permissions to your AndroidManifest.xml.

Expo

🚀 @segment/analytics-react-native 2.0 is compatible with Expo's Custom Dev Client and EAS builds without any additional configuration. Destination Plugins that require native modules may require custom Expo Config Plugins.

⚠️ @segment/analytics-react-native 2.0 is not compatible with Expo Go.

Permissions

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Migrating

See the Migration Guide for a detailed walkthrough of the changes you will need to make when upgrading to analytics-react-native 2.0

Usage

Setting up the client

The package exposes a method called createClient which we can use to create the Segment Analytics client. This central client manages all our tracking events.

import { createClient } from '@segment/analytics-react-native';

const segmentClient = createClient({
  writeKey: 'SEGMENT_API_KEY'
});

You must pass at least the writeKey. Additional configuration options are listed below:

Client Options

* The default value of debug will be false in production.

iOS Deep Link Tracking Setup

Note: This is only required for iOS if you are using the trackDeepLinks option. Android does not require any additional setup

To track deep links in iOS you must add the following to your AppDelegate.m file:

  #import <segment_analytics_react_native-Swift.h>
  
  ...
  
- (BOOL)application:(UIApplication *)application
            openURL: (NSURL *)url
            options:(nonnull NSDictionary<UIApplicationOpenURLOptionsKey, id> *)options {
  
  [AnalyticsReactNative trackDeepLink:url withOptions:options];  
  return YES;
}

Native AnonymousId

If you need to generate an anonymousId either natively or before the Analytics React Native package is initialized, you can send the anonymousId value from native code. The value has to be generated and stored by the caller. For reference, you can find a working example in the app and reference the code below:

iOS

...
#import <segment_analytics_react_native-Swift.h>

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  ...
  // generate your anonymousId value
  // dispatch it across the bridge

  [AnalyticsReactNative setAnonymousId: @"My-New-Native-Id"];
  return yes
}

Android

// MainApplication.java
...
import com.segmentanalyticsreactnative.AnalyticsReactNativePackage;

...
private AnalyticsReactNativePackage analytics = new AnalyticsReactNativePackage();

...
   @Override
    protected List<ReactPackage> getPackages() {
      @SuppressWarnings("UnnecessaryLocalVariable")
      List<ReactPackage> packages = new PackageList(this).getPackages();
      // AnalyticsReactNative will be autolinked by default, but to send the anonymousId before RN startup you need to manually link it to store a reference to the package
      packages.add(analytics);
      return packages;
    }
...
  @Override
  public void onCreate() {
    super.onCreate();
    ...

  // generate your anonymousId value
  // dispatch it across the bridge

  analytics.setAnonymousId("My-New-Native-Id");
  }

Usage with hooks

In order to use the useAnalytics hook within the application, we will additionally need to wrap the application in an AnalyticsProvider. This uses the Context API and will allow access to the analytics client anywhere in the application

import {
  createClient,
  AnalyticsProvider,
} from '@segment/analytics-react-native';

const segmentClient = createClient({
  writeKey: 'SEGMENT_API_KEY'
});

const App = () => (
  <AnalyticsProvider client={segmentClient}>
    <Content />
  </AnalyticsProvider>
);

useAnalytics()

The client methods will be exposed via the useAnalytics() hook:

import React from 'react';
import { Text, TouchableOpacity } from 'react-native';
import { useAnalytics } from '@segment/analytics-react-native';

const Button = () => {
  const { track } = useAnalytics();
  return (
    <TouchableOpacity
      style={styles.button}
      onPress={() => {
        track('Awesome event');
      }}
    >
      <Text style={styles.text}>Press me!</Text>
    </TouchableOpacity>
  );
};

Usage without hooks

The tracking events can also be used without hooks by calling the methods directly on the client:

import {
  createClient,
  AnalyticsProvider,
} from '@segment/analytics-react-native';

// create the client once when the app loads
const segmentClient = createClient({
  writeKey: 'SEGMENT_API_KEY'
});

// track an event using the client instance
segmentClient.track('Awesome event');

Client methods

Track

The track method is how you record any actions your users perform, along with any properties that describe the action.

Method signature:

track: (event: string, properties?: JsonMap) => void;

Example usage:

const { track } = useAnalytics();

track('View Product', {
  productId: 123,
  productName: 'Striped trousers',
});

Screen

The screen call lets you record whenever a user sees a screen in your mobile app, along with any properties about the screen.

Method signature:

screen: (name: string, properties?: JsonMap) => void;

Example usage:

const { screen } = useAnalytics();

screen('ScreenName', {
  productSlug: 'example-product-123',
});

For setting up automatic screen tracking, see the instructions below.

Identify

The identify call lets you tie a user to their actions and record traits about them. This includes a unique user ID and any optional traits you know about them like their email, name, etc. The traits option can include any information you might want to tie to the user, but when using any of the reserved user traits, you should make sure to only use them for their intended meaning.

Method signature:

identify: (userId: string, userTraits?: JsonMap) => void;

Example usage:

const { identify } = useAnalytics();

identify('user-123', {
  username: 'MisterWhiskers',
  email: '[email protected]',
  plan: 'premium',
});

Group

The group API call is how you associate an individual user with a group—be it a company, organization, account, project, team or whatever other crazy name you came up with for the same concept! This includes a unique group ID and any optional group traits you know about them like the company name industry, number of employees, etc. The traits option can include any information you might want to tie to the group, but when using any of the reserved group traits, you should make sure to only use them for their intended meaning.

Method signature:

group: (groupId: string, groupTraits?: JsonMap) => void;

Example usage:

const { group } = useAnalytics();

group('some-company', {
  name: 'Segment',
});

Alias

The alias method is used to merge two user identities, effectively connecting two sets of user data as one. This is an advanced method, but it is required to manage user identities successfully in some of our destinations.

Method signature:

alias: (newUserId: string) => void;

Example usage:

const { alias } = useAnalytics();

alias('user-123');

Reset

The reset method clears the internal state of the library for the current user and group. This is useful for apps where users can log in and out with different identities over time.

Note: Each time you call reset, a new AnonymousId is generated automatically.

Method signature:

reset: () => void;

Example usage:

const { reset } = useAnalytics();

reset();

Flush

By default, the analytics will be sent to the API after 30 seconds or when 20 items have accumulated, whatever happens sooner, and whenever the app resumes if the user has closed the app with some events unsent. These values can be modified by the flushAt and flushInterval config options. You can also trigger a flush event manually.

Method signature:

flush: () => Promise<void>;

Example usage:

const { flush } = useAnalytics();

flush();

(Advanced) Cleanup

You probably don't need this!

In case you need to reinitialize the client, that is, you've called createClient more than once for the same client in your application lifecycle, use this method on the old client to clear any subscriptions and timers first.

let client = createClient({
  writeKey: 'KEY'
});

client.cleanup();

client = createClient({
  writeKey: 'KEY'
});

If you don't do this, the old client instance would still exist and retain the timers, making all your events fire twice.

Ideally, you shouldn't need this though, and the Segment client should be initialized only once in the application lifecycle.

Automatic screen tracking

Sending a screen() event with each navigation action will get tiresome quick, so you'll probably want to track navigation globally. The implementation will be different depending on which library you use for navigation. The two main navigation libraries for React Native are React Navigation and React Native Navigation.

React Navigation

Our example app is set up with screen tracking using React Navigation, so you can use it as a guide.

Essentially what we'll do is find the root level navigation container and call screen() whenever user has navigated to a new screen.

Find the file where you've used the NavigationContainer - the main top level container for React Navigation. In this component, create 2 new refs to store the navigation object and the current route name:

const navigationRef = useRef(null);
const routeNameRef = useRef(null);

Next, pass the ref to NavigationContainer and a function in the onReady prop to store the initial route name. Finally, pass a function in the onStateChange prop of your NavigationContainer that checks for the active route name and calls client.screen() if the route has changes. You can pass in any additional screen parameters as the second argument for screen call as needed.

<NavigationContainer
  ref={navigationRef}
  onReady={() => {
    routeNameRef.current = navigationRef.current.getCurrentRoute().name;
  }}
  onStateChange={() => {
    const previousRouteName = routeNameRef.current;
    const currentRouteName = navigationRef.current?.getCurrentRoute().name;

    if (previousRouteName !== currentRouteName) {
      segmentClient.screen(currentRouteName);
      routeNameRef.current = currentRouteName;
    }
  }}
>

React Native Navigation

In order to setup automatic screen tracking while using React Native Navigation, you will have to use an event listener. That can be done at the point where you are setting up the root of your application (ie. Navigation.setRoot). There your will need access to your SegmentClient.

// Register the event listener for *registerComponentDidAppearListener*
Navigation.events().registerComponentDidAppearListener(({ componentName }) => {
  segmentClient.screen(componentName);
});

Plugins + Timeline architecture

You have complete control over how the events are processed before being uploaded to the Segment API.

In order to customise what happens after an event is created, you can create and place various Plugins along the processing pipeline that an event goes through. This pipeline is referred to as a Timeline.

Plugin Types

Plugins can have their own native code (such as the iOS-only IdfaPlugin) or wrap an underlying library (such as FirebasePlugin which uses react-native-firebase under the hood)

Destination Plugins

Segment is included as a DestinationPlugin out of the box. You can add as many other DestinationPlugins as you like, and upload events and data to them in addition to Segment.

Or if you prefer, you can pass autoAddSegmentDestination = false in the options when setting up your client. This prevents the SegmentDestination plugin from being added automatically for you.

Adding Plugins

You can add a plugin at any time through the segmentClient.add() method.

import { createClient } from '@segment/analytics-react-native';

import { AmplitudeSessionPlugin } from '@segment/analytics-react-native-plugin-amplitude-session';
import { FirebasePlugin } from '@segment/analytics-react-native-plugin-firebase';
import { IdfaPlugin } from '@segment/analytics-react-native-plugin-idfa';

const segmentClient = createClient({
  writeKey: 'SEGMENT_KEY'
});

segmentClient.add({ plugin: new AmplitudeSessionPlugin() });
segmentClient.add({ plugin: new FirebasePlugin() });
segmentClient.add({ plugin: new IdfaPlugin() });

Writing your own Plugins

Plugins are implemented as ES6 Classes. To get started, familiarise yourself with the available classes in /packages/core/src/plugin.ts.

The available plugin classes are:-

• Plugin
• EventPlugin
• DestinationPlugin
• UtilityPlugin
• PlatformPlugin

Any plugins must be an extension of one of these classes.

You can them customise the functionality by overriding different methods on the base class. For example, here is a simple Logger plugin:

// logger.js

import {
  Plugin,
  PluginType,
  SegmentEvent,
} from '@segment/analytics-react-native';

export class Logger extends Plugin {

  // Note that `type` is set as a class property
  // If you do not set a type your plugin will be a `utility` plugin (see Plugin Types above)
  type = PluginType.before;

  execute(event: SegmentEvent) {
    console.log(event);
    return event;
  }
}

// app.js

import { Logger } from './logger';

segmentClient.add({ plugin: new Logger() });

As it overrides the execute() method, this Logger will call console.log for every event going through the Timeline.

Supported Plugins

Refer to the following table for Plugins you can use to meet your tracking needs:

Controlling Upload With Flush Policies

To more granurily control when events are uploaded you can use FlushPolicies. This will override any setting on flushAt and flushInterval, but you can use CountFlushPolicy and TimerFlushPolicy to have the same behaviour respectively.

A Flush Policy defines the strategy for deciding when to flush, this can be on an interval, on a certain time of day, after receiving a certain number of events or even after receiving a particular event. This gives you even more flexibility on when to send event to Segment.

To make use of flush policies you can set them in the configuration of the client:

const client = createClient({
  // ...
  flushPolicies: [
    new CountFlushPolicy(5),
    new TimerFlushPolicy(500),
    new StartupFlushPolicy(),
  ],
});

You can set several policies at a time. Whenever any of them decides it is time for a flush it will trigger an upload of the events. The rest get reset so that their logic restarts after every flush.

That means only the first policy to reach shouldFlush gets to trigger a flush at a time. In the example above either the event count gets to 5 or the timer reaches 500ms, whatever comes first will trigger a flush.

We have several standard FlushPolicies:

• CountFlushPolicy triggers whenever a certain number of events is reached
• TimerFlushPolicy triggers on an interval of milliseconds
• StartupFlushPolicy triggers on client startup only
• BackgroundFlushPolicy triggers when the app goes into the background/inactive.

Adding or removing policies

One of the main advatanges of FlushPolicies is that you can add and remove policies on the fly. This is very powerful when you want to reduce or increase the amount of flushes.

For example you might want to disable flushes if you detect the user has no network:

import NetInfo from "@react-native-community/netinfo";

const policiesIfNetworkIsUp = [
  new CountFlushPolicy(5),
  new TimerFlushPolicy(500),
];

// Create our client with our policies by default
const client = createClient({
  // ...
  flushPolicies: policies,
});

// If we detect the user disconnects from the network remove all flush policies, 
// that way we won't keep attempting to send events to segment but we will still 
// store them for future upload.
// If the network comes back up we add the policies back
const unsubscribe = NetInfo.addEventListener((state) => {
  if (state.isConnected) {
    client.addFlushPolicy(...policiesIfNetworkIsUp);
  } else {
    client.removeFlushPolicy(...policiesIfNetworkIsUp)
  }
});

Creating your own flush policies

You can create a custom FlushPolicy special for your application needs by implementing the FlushPolicy interface. You can also extend the FlushPolicyBase class that already creates and handles the shouldFlush value reset.

A FlushPolicy only needs to implement 2 methods:

• start(): Executed when the flush policy is enabled and added to the client. This is a good place to start background operations, make async calls, configure things before execution
• onEvent(event: SegmentEvent): Gets called on every event tracked by your client
• reset(): Called after a flush is triggered (either by your policy, by another policy or manually)

They also have a shouldFlush observable boolean value. When this is set to true the client will atempt to upload events. Each policy should reset this value to false according to its own logic, although it is pretty common to do it inside the reset method.

export class FlushOnScreenEventsPolicy extends FlushPolicyBase {

  onEvent(event: SegmentEvent): void {
    // Only flush when a screen even happens
    if (event.type === EventType.ScreenEvent) {
      this.shouldFlush.value = true;
    }
  }

  reset(): void {
    // Superclass will reset the shouldFlush value so that the next screen event triggers a flush again
    // But you can also reset the value whenever, say another event comes in or after a timeout
    super.reset();
  }
}

Handling errors

You can handle analytics client errors through the errorHandler option.

The error handler configuration receives a function which will get called whenever an error happens on the analytics client. It will receive an argument of SegmentError type.

You can use this error handling to trigger different behaviours in the client when a problem occurs. For example if the client gets rate limited you could use the error handler to swap flush policies to be less aggressive:

const flushPolicies = [new CountFlushPolicy(5), new TimerFlushPolicy(500)];

const errorHandler = (error: SegmentError) => {
  if (error.type === ErrorType.NetworkServerLimited) {
    // Remove all flush policies
    segmentClient.removeFlushPolicy(...segmentClient.getFlushPolicies());
    // Add less persistent flush policies
    segmentClient.addFlushPolicy(
      new CountFlushPolicy(100),
      new TimerFlushPolicy(5000)
    );
  }
};

const segmentClient = createClient({
  writeKey: 'WRITE_KEY',
  trackAppLifecycleEvents: true,
  collectDeviceId: true,
  debug: true,
  trackDeepLinks: true,
  flushPolicies: flushPolicies,
  errorHandler: errorHandler,
});

The reported errors can be of any of the ErrorType enum values.

Reporting errors from plugins

Plugins can also report errors to the handler by using the .reportInternalError function of the analytics client, we recommend using the ErrorType.PluginError for consistency, and attaching the innerError with the actual exception that was hit:

  try {
    distinctId = await mixpanel.getDistinctId();
  } catch (e) {
    analytics.reportInternalError(
      new SegmentError(ErrorType.PluginError, 'Error: Mixpanel error calling getDistinctId', e)
    );
    analytics.logger.warn(e);
  }

Contributing

See the contributing guide to learn how to contribute to the repository and the development workflow.

Code of Conduct

Before contributing, please also see our code of conduct.

License

MIT